In which of the following reactions will a change in pressure not affect the rate of reaction?

For the chemical reaction $3X_{(g)} + Y_{(g)} \to X_3Y_{(g)}$,the amount of $X_3Y$ at equilibrium is affected by

For the reaction $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$,the forward reaction at constant temperature is favoured by

The equilibrium which remains unaffected by a change in pressure is:

The yellow solution of $Na_2CrO_4$ changes to orange red on passing $CO_2$ gas due to the formation of:

Does the number of moles of reaction products increase,decrease,or remain the same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?
$(a) \quad PCl_{5(g)} \longleftrightarrow PCl_{3(g)} + Cl_{2(g)}$
$(b) \quad CaO_{(s)} + CO_{2(g)} \longleftrightarrow CaCO_{3(s)}$
$(c) \quad 3Fe_{(s)} + 4H_2O_{(g)} \longleftrightarrow Fe_3O_{4(s)} + 4H_{2(g)}$